<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_ym19_1_1461470790420_2816"><span>Sean,</span></div><div id="yui_3_16_0_ym19_1_1461470790420_2812" dir="ltr"><span id="yui_3_16_0_ym19_1_1461470790420_2811">you certainly have all the experience & talents there to build</span></div><div id="yui_3_16_0_ym19_1_1461470790420_2770" dir="ltr"><span id="yui_3_16_0_ym19_1_1461470790420_2771">a decent sub. I guess power boats have dead-man switches</span></div><div id="yui_3_16_0_ym19_1_1461470790420_2876" dir="ltr"><span id="yui_3_16_0_ym19_1_1461470790420_2875">which are a good idea if you are on your own.</span></div><div id="yui_3_16_0_ym19_1_1461470790420_2907" dir="ltr"><span id="yui_3_16_0_ym19_1_1461470790420_2906">My first boat was a suitcase I found in my parents garage, & ripped the lid off.</span></div><div id="yui_3_16_0_ym19_1_1461470790420_2916" dir="ltr"><span id="yui_3_16_0_ym19_1_1461470790420_2915">Sailed it down the local creek with 1" of freeboard & got in a </span><span id="yui_3_16_0_ym19_1_1461470790420_2914">lot of *%#! </span></div><div id="yui_3_16_0_ym19_1_1461470790420_2917" dir="ltr"><span id="yui_3_16_0_ym19_1_1461470790420_2923">over the wrecked suitcase.</span></div><div id="yui_3_16_0_ym19_1_1461470790420_2869" dir="ltr"><span id="yui_3_16_0_ym19_1_1461470790420_2868">Cheers Alan</span></div><div id="yui_3_16_0_ym19_1_1461470790420_2813" dir="ltr"><span id="yui_3_16_0_ym19_1_1461470790420_2847"></span><br></div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1461470790420_2683"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_ym19_1_1461470790420_2838" style="display: block;"> <div id="yui_3_16_0_ym19_1_1461470790420_2837" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1461470790420_2836" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1461470790420_2842" dir="ltr"> <font id="yui_3_16_0_ym19_1_1461470790420_2841" face="Arial" size="2"> <hr size="1" id="yui_3_16_0_ym19_1_1461470790420_2846"> <b><span style="font-weight: bold;">From:</span></b> Sean T. Stevenson via Personal_Submersibles <personal_submersibles@psubs.org><br> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Sunday, April 24, 2016 11:38 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Speed controllers<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_ym19_1_1461470790420_2835"><br><div id="yiv9053894884"><div id="yui_3_16_0_ym19_1_1461470790420_2834"><div id="yui_3_16_0_ym19_1_1461470790420_2840" dir="ltr">Some years ago, I had an earlier career with the Canadian Coast Guard, one aspect of which was operating fast response rescue boats. Zodiac Hurricane 733 with twin 150 HP outboards. We lived by one important rule when operating: one hand on the wheel, one hand on the throttle(s) at all times if not in neutral. Our instructor would actually bash our knuckles with whatever was handy if we slipped up in order to ingrain that habit. Now, granted you can get into more trouble at 50 knots than you can at less than 5, but the idea has always stuck with me.</div>
<div id="yui_3_16_0_ym19_1_1461470790420_2833" dir="ltr">I'm not completely against "cruise control" if properly implemented with safety features (e.g. deadman switch). Certainly I can see this being useful for descent / ascent. I have a tougher time seeing the advantages for navigation of a slow speed submersible.</div>
<div dir="ltr">Sean<br clear="none">
</div>
<br clear="none"><br clear="none"><div class="yiv9053894884yqt4528239023" id="yiv9053894884yqtfd65255"><div class="yiv9053894884gmail_quote">On April 23, 2016 4:49:14 PM MDT, Alan James via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="yiv9053894884gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;">
<div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4738"><span>Hi Sean,</span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4768"><span id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4767">I wasn't advocating a fixed position throttle, however </span><span id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4740">electric start motor boat throttles </span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4776" dir="ltr"><span id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4775">don't have a return to neutral function. I had thought that that was how your </span><span id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4798">set point </span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5129" dir="ltr"><span>system was operating.</span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5145" dir="ltr"><span>Cheers Alan</span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4814" dir="ltr"><span id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4813"></span><br clear="none"></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4770" dir="ltr"><span id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4769"></span><br clear="none"></div><div class="yiv9053894884qtdSeparateBR" id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_4741"><br clear="none"><br clear="none"></div><div class="yiv9053894884yahoo_quoted" id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5085" style="display: block;"> <div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5084" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5083" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5088" dir="ltr"> <font id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5087" face="Arial" size="2"> </font><hr size="1"><font id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5087" face="Arial" size="2"> <b><span style="font-weight: bold;">From:</span></b> Sean T. Stevenson via
Personal_Submersibles <personal_submersibles@psubs.org><br clear="none"> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br clear="none"> <b><span style="font-weight: bold;">Sent:</span></b> Sunday, April 24, 2016 1:00 AM<br clear="none"> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Speed controllers<br clear="none"> </font> </div> <div class="yiv9053894884y_msg_container" id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5082"><br clear="none"><div id="yiv9053894884"><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5081"><div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5086" dir="ltr">Part safety, part allowing for future upgrades. In my mind, if you let go of the controls, the vessel should stop, period. If you have an alarm, leak, fire or something else that demands your immediate attention, you don't want to waste precious time having to null the thruster output before dealing with the other problem. Having the stick(s) spring return to zero outpu!
t when
you let go is just prudent, so you (hopefully) don't crash into anything when you have to let go in an emergency, or when you drop your pencil on the floor and throw your back out when you bend over to retrieve it. I would employ self nulling controls regardless of whether I was using direct or indirect control.</div>
<div id="yiv9053894884yui_3_16_0_ym19_1_1461444999852_5080" dir="ltr">With the indirect scheme I proposed, there is an additional advantage to be gained in the presence of sensing mechanisms for vessel motion (surge, sway, heave, yaw, roll and pitch) such as the ubiquitous pressure transducer for depth, gyro/fluxgate compass for heading, or e.g. Doppler velocity log for over bottom motion. In these cases, a control loop provides the ability to null vessel motion, as opposed to simply nulling thruster output, so that if you let go of the controls, the system can automatically apply reverse thrust to cancel headway or compensate for slight currents etc. to keep the vessel where it was when you let go.</div>
<div dir="ltr">This is particularly useful in the case of vertical motion. I intend to implement such a depth controller so that I drive up / down with the stick, with full range on the stick corresponding to 100% thruster output, but when I let go, the current depth becomes the setpoint and the controller takes over, commanding the vertical thrusters as appropriate to maintain that depth. Furthermore, in the event that maintaining that depth then requires a sustained thruster output in either direction, the variable ballast system will automatically adjust in order to bring that necessary thruster output down to zero and thus conserve power.</div>
<div dir="ltr">Sean</div>
<br clear="none"><br clear="none"><div class="yiv9053894884yqt1396958694" id="yiv9053894884yqtfd14402"><div class="yiv9053894884gmail_quote">On April 22, 2016 11:13:19 PM MDT, Alan James via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="yiv9053894884gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;">
<div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3725"><span>Not quite following that Sean,</span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3578" dir="ltr"><span id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3577">why not have a joystick without return to center function &</span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3580" dir="ltr"><span id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3579">leave it on that setting? I can see the sense in running the joystick through</span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3617" dir="ltr"><span id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3618">the PLC with an over-ride on the vertical thrusters when on the depth limit,</span></div><div dir="ltr"><span id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3727">I have seen commercial psubs with this feature.</span></div><div dir="ltr"><span>Alan</span></div><div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3679" dir="ltr"><span id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3696"></span><br clear="none"></div><div class="yiv9053894884qtdSeparateBR" id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3520"><br clear="none"><br clear="none"></div><div class="yiv9053894884yahoo_quoted" id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3476" style="display: block;"> <div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3475" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3474" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3583" dir="ltr"> <font id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3582" face="Arial" size="2"> </font><hr size="1" id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3581"><font id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3582" face="Arial" size="2"> <b><span style="font-weight: bold;">From:</span></b> Sean T. St!
evenson
via Personal_Submersibles <personal_submersibles@psubs.org><br clear="none"> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br clear="none"> <b><span style="font-weight: bold;">Sent:</span></b> Saturday, April 23, 2016 4:31 PM<br clear="none"> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Speed controllers<br clear="none"> </font> </div> <div class="yiv9053894884y_msg_container" id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3473"><br clear="none"><div id="yiv9053894884"><div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3584" dir="ltr">Late to this thread, but I'll throw in my $0.02:</div>
<div id="yiv9053894884yui_3_16_0_ym19_1_1461386657244_3472" dir="ltr">I had envisioned a control scheme whereby the joystick inputs are decoupled from direct thruster / ballast control output. Instead, the PAC runs the thruster outputs on the basis of PID control loops, where the setpoints are adjusted by the pilot controls. Thus, the ramp rate of the target setpoint is dependent on how far e.g. the joystick is pushed or rotated, but on letting go, the stick springs back to center, and at that point the setpoint is overwritten with the current depth, heading or what have you, and the system automatically maintains that setting until you touch the controls again. Manually commanded fully automatic.</div>
<div dir="ltr">Sean<br clear="none">
</div>
</div><br clear="none">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a href="mailto:Personal_Submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"><br clear="none"><br clear="none"></div> </div> </div> </div></div><div style="margin-top: 2.5em; margin-bottom: 1em; border-bottom-color: rgb(0, 0, 0); border-bottom-width: 1px; border-bottom-style: solid;"></div><pre class="yiv9053894884k9mail"></pre><hr><br clear="none">Personal_Submersibles mailing list<br clear="none">Personal_Submersibles@psubs.org<br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></blockquote></div></div></div></div><br clear="none"><div class="yiv9053894884yqt1396958694" id="yiv9053894884yqtfd07607">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a href="mailto:Personal_Submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div><br clear="none"><br clear="none"></div> </div> </div> </div></div><div style="margin-top: 2.5em; margin-bottom: 1em; border-bottom-color: rgb(0, 0, 0); border-bottom-width: 1px; border-bottom-style: solid;"></div><pre class="yiv9053894884k9mail"></pre><hr><br clear="none">Personal_Submersibles mailing list<br clear="none">Personal_Submersibles@psubs.org<br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></blockquote></div></div></div></div><br><div class="yqt4528239023" id="yqtfd61093">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a href="mailto:Personal_Submersibles@psubs.org" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div><br><br></div> </div> </div> </div></div></body></html>